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![Takashi Iwai](/assets/img/avatar_default.png)
Current hdac_i915 uses a static completion instance to wait
for i915 driver to complete the component bind.
This design is not safe if multiple HDA controllers are active and
communicating with different i915 instances, and can lead to list
corruption and failed audio driver probe.
Fix the design by moving completion mechanism to common acomp
code and remove the related code from hdac_i915.
Fixes: 7b882fe3e3
("ALSA: hda - handle multiple i915 device instances")
Co-developed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20201006161722.500256-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
175 lines
4.2 KiB
C
175 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* hdac_i915.c - routines for sync between HD-A core and i915 display driver
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <sound/core.h>
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#include <sound/hdaudio.h>
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#include <sound/hda_i915.h>
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#include <sound/hda_register.h>
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#define IS_HSW_CONTROLLER(pci) (((pci)->device == 0x0a0c) || \
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((pci)->device == 0x0c0c) || \
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((pci)->device == 0x0d0c) || \
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((pci)->device == 0x160c))
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/**
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* snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
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* @bus: HDA core bus
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*
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* Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
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* depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
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* are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
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* BCLK = CDCLK * M / N
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* The values will be lost when the display power well is disabled and need to
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* be restored to avoid abnormal playback speed.
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*
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* Call this function at initializing and changing power well, as well as
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* at ELD notifier for the hotplug.
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*/
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void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
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{
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struct drm_audio_component *acomp = bus->audio_component;
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struct pci_dev *pci = to_pci_dev(bus->dev);
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int cdclk_freq;
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unsigned int bclk_m, bclk_n;
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if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
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return; /* only for i915 binding */
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if (!IS_HSW_CONTROLLER(pci))
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return; /* only HSW/BDW */
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cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
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switch (cdclk_freq) {
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case 337500:
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bclk_m = 16;
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bclk_n = 225;
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break;
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case 450000:
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default: /* default CDCLK 450MHz */
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bclk_m = 4;
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bclk_n = 75;
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break;
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case 540000:
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bclk_m = 4;
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bclk_n = 90;
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break;
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case 675000:
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bclk_m = 8;
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bclk_n = 225;
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break;
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}
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snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
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snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
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}
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EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
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/* returns true if the devices can be connected for audio */
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static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac)
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{
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struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus;
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/* directly connected on the same bus */
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if (bus_a == bus_b)
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return true;
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/*
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* on i915 discrete GPUs with embedded HDA audio, the two
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* devices are connected via 2nd level PCI bridge
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*/
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bus_a = bus_a->parent;
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bus_b = bus_b->parent;
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if (!bus_a || !bus_b)
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return false;
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bus_a = bus_a->parent;
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bus_b = bus_b->parent;
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if (bus_a && bus_a == bus_b)
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return true;
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return false;
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}
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static int i915_component_master_match(struct device *dev, int subcomponent,
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void *data)
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{
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struct pci_dev *hdac_pci, *i915_pci;
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struct hdac_bus *bus = data;
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if (!dev_is_pci(dev))
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return 0;
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hdac_pci = to_pci_dev(bus->dev);
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i915_pci = to_pci_dev(dev);
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if (!strcmp(dev->driver->name, "i915") &&
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subcomponent == I915_COMPONENT_AUDIO &&
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connectivity_check(i915_pci, hdac_pci))
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return 1;
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return 0;
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}
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/* check whether intel graphics is present */
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static bool i915_gfx_present(void)
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{
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static const struct pci_device_id ids[] = {
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{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
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.class = PCI_BASE_CLASS_DISPLAY << 16,
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.class_mask = 0xff << 16 },
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{}
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};
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return pci_dev_present(ids);
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}
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/**
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* snd_hdac_i915_init - Initialize i915 audio component
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* @bus: HDA core bus
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*
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* This function is supposed to be used only by a HD-audio controller
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* driver that needs the interaction with i915 graphics.
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*
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* This function initializes and sets up the audio component to communicate
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* with i915 graphics driver.
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*
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* Returns zero for success or a negative error code.
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*/
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int snd_hdac_i915_init(struct hdac_bus *bus)
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{
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struct drm_audio_component *acomp;
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int err;
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if (!i915_gfx_present())
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return -ENODEV;
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err = snd_hdac_acomp_init(bus, NULL,
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i915_component_master_match,
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sizeof(struct i915_audio_component) - sizeof(*acomp));
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if (err < 0)
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return err;
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acomp = bus->audio_component;
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if (!acomp)
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return -ENODEV;
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if (!acomp->ops) {
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if (!IS_ENABLED(CONFIG_MODULES) ||
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!request_module("i915")) {
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/* 60s timeout */
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wait_for_completion_timeout(&acomp->master_bind_complete,
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msecs_to_jiffies(60 * 1000));
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}
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}
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if (!acomp->ops) {
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dev_info(bus->dev, "couldn't bind with audio component\n");
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snd_hdac_acomp_exit(bus);
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return -ENODEV;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(snd_hdac_i915_init);
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